Process for sizing warp yarns



June 25, 19 D. M. MARTIN PROCESS FOR SIZING WARP YARNS Filed 001;. 28, 1942 IN VEN TOR. DONALD M. MAR TIN ATTQEACEZT i Patented June 25, 1946 UNITED: STATES PATENT OFFICE PROCESSFOR SIZING WARP YARNS Donald M. Martin, Tenafly, N. 1., assignor to Aqua-Sec Corporation, New York, N. Y., a corporation of New York Application October 28. 1942, Serial No. 463,620

starch, gum, dextrine, gelatine and other watersoluble colloids to facilitate weaving the yarns.

However, the speed of slashing warp yarns with such water-soluble colloids is relatively low due to a number of factors including (a) the high viscosity of starch solutions employed, (b) the slow penetration of the viscous solutions, (0) the high temperature required during drying the sized yarns and the low drying ratio. Moreover, the use of these water-soluble substances as a warp sizing is attendant with certain inherent disadvantages.

Thewater-soluble size is not laundry resistant so that it is necessary to remove it after weaving, otherwise the woven fabric will show a pronounced decrease in stiffness after the first laundering. This pronounced change has been the cause of much dissatisfaction on the part of the purchasers because the sized yarn ives to the fabric a temporary appearance of a higher yar'n count and closer weave than is actually present in the fabric.

Moreover, if it isdesired to dye, merceriae, or

bleach the yarn or fabrics made with such sized warp yarns, it is first necessary to desize the yarn as by kier boiling. Such operations always cause a softening and loosening up of the yarn structure resulting in a decrease in the yarn resistance.

Further, warp yarn sized with starch have a low resistance to abrasion and thus fall short of the desired result. The friction caused by the drop wires and the heddles, as well as by transverse movement of thebobbin containing the filling yarn tends to raise the nap on starch sized yarns, thus resulting in the shedding of loose fibers. Finally, in weaving starch sized warp yarns, it has been found necessary to carry out the weaving operation in an atmosphere of relatively high humidity, which tends to corrode the metal parts of the loom, in particular the drop wires.

Accordingly, it is the general object of the present invention to provide a method of slashing warp yarns in a rapid and economical manner and which will enable them to be woven faster and with fewer difliculties than with prior warp sizedyarns.

Another object is to provide a, woven fabric 2 which'does not have to be removed before dyeins, mercerizing, or bleaching.

A more specific object of the invention is to provide a method for permanently sizing warp yarns prior to weaving.

A further specific object of the invention is to provide an apparatus for slashing warp yarns at a greater speed and with reduced cost over that required for slashing warp yarns with starch and the like. c

Other objects of the invention will in part be obvious and will in part appear hereinafter,

According to the present invention, there is provided a process of making a woven fabric by sizing the warp yarns prior to weaving with an alkali-soluble water-insoluble cellulosic colloid and weaving the yarns. More particulary the invention includes the process of collectively treating a multiplicity of warp yarns while arranged in the form of a weftless web with an alkaline dispersion of an alkali-soluble water-insoluble cellulosic colloid, separately coagulating said colloid on the individual warp yarns and weaving said yarns. Thus, the invention provides a woven fabric comprising warp yarns individually sized with a water-insoluble colloid which permanently lays the nap and stabilizes the twist of the yarn. The apparatus of the invention comprises, in combination, means to treat warp yarn in the form of a weftless web, with an aqueous dispersion of a water-insoluble coagulable colloid, means to separate the yarns, means for coagulating the colloid on the yarns while so separated, and means for drying the yarns. The apparatus preferably includes means for separating the yarns before and after coagulating the colloid thereon whereby the yarns do not adhere to each other in passing through subsequent treating comprising warp yarns having a ermanent size devices.

The invention accordingly comprises a process having the steps and the relation of the steps one to another, and an apparatus having the elements and relation of elements, one to another,

as set forth in the following detailed description v and the scope of the application of which will be indicated in the claims.

The present process is applicable for slashing singles yarns and plied yarns of all typos, in particular, warp yarns comprising cotton, ramie, jute, flax, casein fibre, rayon, also fibres formed of synthetic resins, such as vinyon, vinylidene chloride and nylon, or mixtures of these fibres, and whether carded or combed, or made of continuous filaments.

The permanent sizing composition of the presout invention comprises, in general, an aqueous dispersion, preferably an alkaline dispersion of alkali-soluble water-insoluble cellulosic colloid. For the cellulosic colloid there may be employed the alkali-soluble water-insoluble cellulosic ethers as a class, such for example as alky-cellulose ether, hydroxy-alkyl cellulose ether, carboxyalkyl cellulose ether, and the like; also, the alkali-soluble water-insoluble cellulose materials per se as a class such, for example, as cellulose dissolving in any of its known solvents such as an alkali solution of 5% to concentration, alkaline solutions of zincates, and stannates, or strong organic bases such as aralkyl ammonium hydroxides; also alkali-soluble water-insolubledegraded cellulose such, for example, as the degraded cellulose solutions disclosed in the copending U. S. application, Serial Number 427,389, filed January 19, 1942, and the degraded cellulose solutions disclosed in U. S. Patent 2,289,085, and in British Patent 507,138.

Among the cellulose other solutions, there is preferred an alkali-soluble water-insoluble hydroxy-ethyl cellulose ether dissolved in an aqueous alkali solution, and among the cellulosic solutions,

there is preferred a degraded cellulose dissolved in an aqueous alkaline zincate solution as disclosed in U. S. Patent 2,289,085.

The cellulosic colloid may 'be coagulated from its alkaline dispersion by means of any of the known coagulants for viscose such, for example, acids, acid salts, salts and heat, also by the action of hot water.

The alkaline dispersion of the cellulose colloid is preferably applied to the yarn while the dispersion has a low viscosity. It is characteristic of the degraded cellulose solutions above disclosed that their alkaline dispersions have very low viscosities. However, alkali solutions of the cellulose ethers may be made of low viscosity either (a) by degrading the cellulose ether before or. after its manufacture by the use of heat alone or by heating with acids, alkalies, or oxidizing agents; or (b) the viscosity of the alkaline solutions may be lowered by adding to the solution an oxidizing agent such, for example, as ammonium persulfate, alkali perborates, alkali perchlorate's, hydrogen peroxide, and the like; or by h atin the aqueous alkaline solution of th cel- .lulose ether during application to the yarn to a temperature at which it shows a. pronounced drop in viscosity such, for example, at a temperature between 140 to 160 F.

The cellulosic content of the alkaline dispersion may be varied over a wide range, but usually if the dispersion contains from 3% to 8%, preferably about 6% by weight of the solution of the cellulosic colloid, a satisfactory warp sizing will be obtained. The quantity of alkali, which is normally a strong alkali such as sodium hydroxide, potassium hydroxide or aralkyl ammonium hydroxide, may-be varied according to the amount required to completely and uniformly disperse the cellulosic colloid, which amount is usually between 5% and 10% by weight of the solution.

To the dispersion there may also be added a wetting agent such, for example, a sulfated fatty alcohol, a sulfonated fatty acid, and the like.

Likewise, there may be added to the sizing composition, pigments or dyestuffs which are stable in alkali. Since the sizing agent will not be removed after weaving nor during laundering, the pigments or dyestufis will serve to permanently color the yarns, a feature which can not be achieved by the use of conventional starch or 1, 4 other water-soluble colloids. The coagulated water-insoluble colloid serves to permanently bind the pigments or dyestuffs to the yarns.

For a more complete understanding of the nature and objects of the present invention, reference should be had to the accompanying drawing in which there is illustrated one embodiment of the apparatus of the invention for permanently sizing warp yarns.

Referring to the accompanying drawing, the warp yarns H! are unwound from the beam I l and passed into the sizing composition. held in the first box l2 of a four-box slasher. The box |2 is provided with a jacket Hi and, in the space so provided, hot water is introduced through the pipe l4 and withdrawn through the pipe |5. The remaining boxes l6, l1, and I8 of the slasher are substantially identical in construction, and each is provided with a submerged roller I9, and a pair of pressure rollers 20 positioned above each box respectively so that the excess liquid carried by the yarns is caused to flow back into the respective box. The pressure rollers 2| and '22 at the exit of the box |2 are of special construction. It has been found that to avoid flattening the yarns and to produce an even distribution of the size thereon, one or both of the rollers 2| and 22 is provided with a very rough surface, for example, by wrapping the roller with a very rough fabric such, for example asburlap. The top roller 2| will normally be the wrapped roller and the bottom roller 22 will be a roller provided with a soft resilient surface such as rubber. The rollers are provided with a means (not shown) for subjecting the yarn to substantial pressure as it passes between the rollers. From the nip of the rollers 2| and 22 the sized warp yarns are separated by a leash or splitter rod 23, and the cellulosic colloid coagulated as the yarn passes through a liquid coagulant contained in box IE. After coagulation the yarns are again separated by a leash or splitter rod 23. The yarns are washed in hot water contained in box l1 and then subjected to a second washing. with dilute alkali in the box l8. After this treatment, the sized yarns are dried by suitable means as by passing them over and under the heated drying cans 24 and 25, and the dried yarns are then wound upon the beam 26, which may be a split beam. To prevent overlapping of the yarns one upon the other there may be provided, at suitable points in the course of travel, combs or reeds 1 21 of conventional design, such reeds being shown in the figure at points where the yarns leave the box H, the box l8, and before and after they pass over the drying cans.

It is important and highly desirable that the warp yarns be separated by passing alternate yarns over and under the leash or splitter rods 23 and 23 before and after coagulation of the cellulosiccolloid, since the coagulation of the colloid on contacting yarns tends to cause the yarns to adhere to each other.

By way of illustrating, but not by way of limit ing the invention, there will be given the following specific example.

. Combed or carded cotton warp yarns, intended for use in twills or drills for military uniforms,

are sized by passing the yarns through a sizing compared to glycerin), 8% sodium hydroxide, and

5 to between 0.5 and 0.1. The sizing composition is placed in the box I! of the apparatus shown in the drawing and the composition heated to a temperature of 150 F. The warp yarns are passed successively through the hot composition contained in box til, then through the pressure rollers 2i and 22, separated by the leash rod 23, and then passed into the box is containing a 5% aqueous solution of sulphuric acid as a coagulant.

The excess coagulant is squeezed out b means of the pressure rollers- 20, the yarn separated by the rod 23, and then washed in water contained in the box i1 heated to 140 F. Finally, the yarns are subjected in the box It to washing with an aqueous solution of 5% ammonia, and the washed yarns are then dried on the cans 24 and 25,

It has been found that when the cellulose ether is coagulated and finally dried on the yarns, the coagulated colloid shrinks and draws the nap fibers of the yarn into the body, that is, it lays the nap and provides the yarn with a smooth surface distinctly different from that produced when such yarns are sized with starch. Moreover, since the fibers in the yarn are now bound to each other by the water-insoluble binding agent, the yarn twist is stabilized and the tendency of the fibres and/or plies to separate is decreased. Also the permanent sizing agent herein provided sets the dimensions of the yarn and thereby reduces shrinkage during repeated laundering. Warp yarns sized with the composition of the present invention showed a marked decrease in the shedding of fibers during weaving because the friction of the drop needle or wires and heddles, and the transverse movement of the bobbin does not raise a nap on the yarn but, in contrast with starch sized yarns, such friction tends to make the present yarns smoother.

It is obvious that the present process and apparatus embodies many advantages over conventional methods of slashing warp yarns with starch solutions. In the first place, the alkali employed in the present composition tends to swell the yarns and this promotes the more rapid penetration of size into the interior of the yarn. Unlike starch, the dispersions of alkali-soluble water-insoluble cellulosic colloids can be reduced in viscosity by simple means above described thus increasing the speed with which the yarns may be passed through the sizing composition. Moreover, the yarns of the present invention can be woven at normal atmospheric humidity since the cellulosic colloid appears to be relatively more hydroscopic than starch, thus the costly humidifying devices required for weaving starch-slashed yarns may be eliminated. Finally, the present yarns need not be desized or kiss-boiled before dyeing, and/or mercerizing, and/il bleaching the yarns. Since the cellulosic colloid is not removed during these operations and does not interfere with the dyeing, mercerizing, or bleaching, where specifications limit the non-cotton content of warp yarns, the present process enables such specifications to be met more readily than with starch because the sizing agent applied herein is itself cellulosic.

It is obvious that certain changescan be made in the process and apparatus without transcending the scope of the invention. If desired, there may be added to the sizing composition compatible colloids, such for example as rubber latex,

alkali-soluble synthetic resins, wetting agents and other materials for improving the properties and characteristics of the warp yarns.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a process for sizing warp yarns, the steps comprising treating an alkaline dispersion of an alkali-soluble water-insoluble cellulosic colloid with an oxidizing agent to lower the viscosity, individually treating warp yarns with said low viscosity dispersion, subjecting the treated yarns to pressure to cause the dispersion to impregnate the yarns, coagulating said colloid within the yarns, and drying the impregnated yarns.

2. A process for sizing warp yarns, comprising degrading an alkaline dispersion of an alkalisoluble water-insoluble cellulosic colloid to lower the viscosity, individually treating warp yarns with said low viscosity dispersion, subjecting the treated yarns to pressure to cause the dispersion to impregnate the yarns, coagulating the colloid within the yarn; while maintaining the yarns separate from each other, and drying the impregnated yarns.

3. A process for sizing warp yarns, comprising degrading an alkaline dispersion of an alkalisoluble water-insoluble cellulose ether to lower the viscosity, individually treating warp yarns with said low viscosity dispersion, subjecting the treated yarns to pressure to cause the dispersion to impregnate the yarns, coagulating the cellulose ether within the yarns while maintaining the yarns separate from each other, and drying the DONALD M. MARTIN. 

